Spectra of 4D, N=1 Type I String Vacua on Non-Toroidal CY Threefolds

TL;DR

This paper calculates the massless spectra of 4D N=1 type I string vacua on non-toroidal Calabi-Yau threefolds using Gepner models, revealing unexpectedly large gauge groups.

Contribution

It provides the first detailed conformal field theory analysis of type I string compactifications on non-toroidal Calabi-Yau manifolds at special moduli points.

Findings

Large gauge groups such as SO(12) x SO(20) identified

Spectra computed using Gepner model techniques

Surprising gauge group sizes compared to toroidal cases

Abstract

We compute the massless spectra of some four dimensional, N=1 supersymmetric compactifications of the type I string. The backgrounds are non-toroidal Calabi-Yau manifolds described at special points in moduli space by Gepner models. Surprisingly, the abstract conformal field theory computation reveals Chan-Paton gauge groups as big as SO(12) x SO(20) or SO(8)^4 x SO(4)^3.